State Key Laboratory of Microbial Technology, Shandong University, 266237, Qingdao, P. R. China.
Marine Biology Institute, Shantou University, 515063, Shantou, P. R. China.
Nat Commun. 2023 Dec 20;14(1):8480. doi: 10.1038/s41467-023-44245-4.
Succinic acid (SA) is an important C4-dicarboxylic acid. Microbial production of SA at low pH results in low purification costs and hence good overall process economics. However, redox imbalances limited SA biosynthesis from glucose via the reductive tricarboxylic acid (TCA) cycle in yeast. Here, we engineer the strictly aerobic yeast Yarrowia lipolytica for efficient SA production without pH control. Introduction of the reductive TCA cycle into the cytosol of a succinate dehydrogenase-disrupted yeast strain causes arrested cell growth. Although adaptive laboratory evolution restores cell growth, limited NADH supply restricts SA production. Reconfiguration of the reductive SA biosynthesis pathway in the mitochondria through coupling the oxidative and reductive TCA cycle for NADH regeneration results in improved SA production. In pilot-scale fermentation, the engineered strain produces 111.9 g/L SA with a yield of 0.79 g/g glucose within 62 h. This study paves the way for industrial production of biobased SA.
琥珀酸（SA）是一种重要的 C4-二羧酸。在低 pH 值条件下微生物生产 SA 可降低纯化成本，从而具有良好的整体工艺经济性。然而，氧化还原失衡限制了酵母通过还原性三羧酸（TCA）循环从葡萄糖合成 SA。在这里，我们通过工程化严格需氧酵母解脂耶氏酵母（Yarrowia lipolytica）来生产 SA，无需 pH 控制。将还原性 TCA 循环引入琥珀酸脱氢酶缺陷酵母菌株的细胞质中会导致细胞生长停滞。虽然适应性实验室进化恢复了细胞生长，但 NADH 的有限供应限制了 SA 的生产。通过将氧化和还原性 TCA 循环偶联起来以再生 NADH，重新配置线粒体中的还原性 SA 生物合成途径，可提高 SA 的生产。在中试规模发酵中，该工程菌株在 62 小时内产生 111.9 g/L 的 SA，葡萄糖得率为 0.79 g/g。这项研究为生物基 SA 的工业化生产铺平了道路。
